Logic Card Self-Diagnostic Technique for Driver/Receiver Fault Detection on the Bidirectional Interface to a Remote Data Bus
Original Publication Date: 1985-Mar-01
Included in the Prior Art Database: 2005-Feb-18
A technique is described whereby a logic circuit card is used to detect faults in a bidirectional data bus that is physically connected to a remote device. The circuit is particularly useful whenever the logic card is used as a host controller interfaced to a remote device and whenever conversion is required from a byte-wide data bus at the interface to a word-wide data bus. Microprocessor design techniques frequently implement automatic diagnostics, of the operational logic, at power-on time. Usually, the first instruction executed by the microprocessor, after a power-on reset, is a routine that writes and then reads data from registers and latches in order to verify fault-free operation. Considerable difficulty may be experienced in fault-testing drivers and receivers that interface to remote devices.